"The included two-channel USB audio interface was recognised immediately by my Mac system, without the need to add any driver software, and the subjective audio quality I achieved from it was surprisingly good. In all, I feel the upgrade to this already workmanlike little mixer has been highly worthwhile, and within its price range it now offers a lot of flexibility to both the home studio owner and the band looking for a small live sound mixer with integral effects."

I think the Q502USB is a pretty good option for someone who wants an inexpensive option to be able to add vocals or play Pianoteq along with an mp3 player added to the mix.

However, many on a budget will want to spend an extra $40-$50 to get a similar product that delivers 24 bit and 96,000Hz capability.

Thanks so much for correcting me on this one and the USB vs MIDI question. In the future, I will gladly leave these technicalities to the experts.

I wouldn't call myself an expert. I know that there are multiple timing and latency problems with MIDI, but I am not a professional music producer, so I don't know all of the specifics. Whether the hardware limitations pose a problem also largely depends on what you are trying to achieve. Cable length can definitely be an issue, but im my opinion not because of latency but rather because of signal quality: I would be at least careful (i.e., use quality cabling) with anything longer than 10 metres (30ft). I know just enough from my physicist/programmer point of view to be able to state that in 'simple' scenarios like the ones discussed here, there shouldn't be much of a practical problem.

This is physically improbable. The MIDI signal is a serial connection of about 31250 bits/second. Since it is serial, latency between channels actually is an issue. But the electric wave in the wire travels at near-lightspeed, i.e., several hundreds of thousands of kilometers per second. In other words: if you change the voltage on one end of a cable, even if it is 10 metres (~30ft) long, the change reaches the other end in less than 50 nanoseconds.

Thanks so much for correcting me on this one and the USB vs MIDI question. In the future, I will gladly leave these technicalities to the experts.

kalessin: With something like the Steinberg, do you plug the keyboard into the midi input? I am currently using a midi to usb cable and then crappy onboard soundcard. Wondering if I upgrade to an external soundcard if I should plan on connecting the keyboard to the soundcard too instead of to a usb port on the laptop....

That should not make much of a difference, other than wasting a USB port if you don't. Most modern keyboards have built-in USB anyway (and an increasing number even drops the old hardware MIDI ports). If you use an interface like the Steinberg UR22, if you use the built-in MIDI port or an external converter cable will make not much of a difference. The Steinberg interface might be a little bit superior in terms of latency and jitter, but to be honest you will probably not notice anything. But on the other hand, why waste that USB port when the UR22 provides a MIDI port anyway?

The question of latency and jitter when using MIDI over USB is actually a rather contentiously discussed one; in theory USB is not a real-time transport and thus actually can (and does, to a degree) introduce increased latency and jitter. In practice, most of the time you will not notice anything, especially in the case we are discussing here: a single keyboard controlling a virtual instrument. Jitter becomes important when you control many different hardware devices all at once, but as far as I know this is not really the way things are done anymore in the days of DAWs and virtual instruments.

This is physically improbable. The MIDI signal is a serial connection of about 31250 bits/second. Since it is serial, latency between channels actually is an issue. But the electromagnetic wave in the wire travels at near-lightspeed, i.e., several hundreds of thousands of kilometers per second. In other words: if you change the voltage on one end of a cable, even if it is 10 metres (~30ft) long, the change reaches the other end in less than 50 nanoseconds.

Cheap sound cards can and often do suffer from several artefacts:

• A mixture of white, pink, red noise

• 'Humming' sounds due to bad electrical de-coupling (this is also especially true for the cheap USB stick-like devices)

• Clipping

• Distortion: a bad sound card can sound like listening through a cheap band pass filter

• Aliasing: when the sampled signal is not reconstructed correctly (Nyquist-Shannon theorem), the result are artefacts in the higher frequencies. Similar effects happen when working with 96kHz audio and not properly downsampling.

• Badly-done dithering: audible as a nasty "hissing" sound whenever certain sounds are played that are rich in high frequencies (violins, pianos, electrical guitars). Especially problematic on low volumes; this is an effect almost every single mobile device (smartphone, tablet) I know shows.

My most notorious example for these is a SoundBlaster Play! I have lying around here. That is after all a device for around 25-30 bucks. It shows audible humming on certain USB ports, especially on hubs (and Creative still advertises a SNR of 90dB!), it hisses and it produces aliasing so bad that the built-in sound of my tablet is actually better...

kalessin: With something like the Steinberg, do you plug the keyboard into the midi input? I am currently using a midi to usb cable and then crappy onboard soundcard. Wondering if I upgrade to an external soundcard if I should plan on connecting the keyboard to the soundcard too instead of to a usb port on the laptop....

To my knowledge, it doesn't make much of a difference. However, you might get slightly lower latency connecting your keyboard's MIDI directly to the computer than to the MIDI input of a USB audio interface. I have read also that a long MIDI cable, 10 ft or more, can introduce latency as a sound issue.

I did notice a little bit of hum and white noise when I used my desktop's sound card which disappeared when I started using a quality PCI sound card and what I'm currently using, the Behringer Xenyx Q502USB.

I must say that the Behringer is super quiet when I play the piano, and I couldn't tell the difference in sound quality between it and a fancy tube headphone amp. Albeit, I'm not an audiophile, and there might be things like listener fatigue, subconscious stuff.

The main things I have in bad memory are noisy pre-amps and distortion. In general I have had more examples of cheap sound devices not managing even the basics (i.e., noise, clipping or correct sample reconstruction according to Shannon-Nyquist) than I care to remember. I do not know if the Xenyx has a Problem with aliasing artefacts, and maybe Behringer finally got their act together in terms of the pre-amps. Then it might just work, if you don't expect super-linear behaviour.

Well... there's nothing more expensive than buying too cheap. If the choice is between a (quite noisy) live mixer for fifty bucks or a decent USB sound device for a hundred, I know what I would choose. Devices like the Steinberg UR22 are a farcry from anything Behringer makes, and are not that expensive. I like the Behringer monitor speakers (like the 2030A and 2031A), but apart from that I cannot say many positive things about the audio quality of any Behringer equipment I tried. Of course it's your money.

The Steinberg looks like a good choice. The signal to noise ratio on the Steinberg is the same as the Behringer.

I must say that the Behringer is super quiet when I play the piano, and I couldn't tell the difference in sound quality between it and a fancy tube headphone amp. Albeit, I'm not an audiophile, and there might be things like listener fatigue, subconscious stuff.

If I were on a budget, but wanted to make sure I was getting the best sound within that budget, I would pick up both the Behringer and the Steinberg used, spend some time comparing, and sell whichever one loses on price or quality.

That's a neat idea!  I never thought of using the Behringer USB mixer as a soundcard.  But it's cheaper than most things sold as soundcards, and probably works fine.

Well... there's nothing more expensive than buying too cheap. If the choice is between a (quite noisy) live mixer for fifty bucks or a decent USB sound device for a hundred, I know what I would choose. Devices like the Steinberg UR22 are a farcry from anything Behringer makes, and are not that expensive. I like the Behringer monitor speakers (like the 2030A and 2031A), but apart from that I cannot say many positive things about the audio quality of any Behringer equipment I tried. Of course it's your money.

  . . .

Since using a Xenyx Q502USB mixer with ASIO4ALL, I'm using less than 50% peak CPU on my 2800ghz dual core computer with 2.7ms latency (I get occasional clipping at 1.3ms), 4800 HZ external and internal sample rate, 128 polyphony, hi res MIDI.

Operation is seamless.

That's a neat idea!  I never thought of using the Behringer USB mixer as a soundcard.  But it's cheaper than most things sold as soundcards, and probably works fine.

One more thing on the shopping list . . . <g>

.          Charles

Just curious....

Since using a Xenyx Q502USB mixer with ASIO4ALL, I'm using less than 50% peak CPU on my 2800ghz dual core computer with 2.7ms latency (I get occasional clipping at 1.3ms), 4800 HZ external and internal sample rate, 128 polyphony, hi res MIDI.

Operation is seamless.